asbestos crayons
© Reuters / Michaela Rehle
Asbestos fibers have been found in crayons and children's toys sold in the US, according to a new report from a health advocacy group.

The EWG Action Fund is calling for a ban on asbestos in consumer products after it found the substance in four out of 28 brands of crayons, according to a report released by the group on Wednesday.

Two brands of toy crime-lab kits of the 21 which were tested were also reported to have contained the carcinogenic substances. They had been purchased from ToysRUs.com and Amazon.com. Asbestos was found in the kits' fingerprint dusting powders, and these products had higher concentrations than the tested brand of crayon did.

"We were surprised," report co-author Sonya Lunder told CBS News. "Crayons and crime-scene toys were found to have asbestos in years gone by, and the manufacturers of both had already promised to deal with the problem," she explained, noting that all the products that tested positive were manufactured in China.

Breathing in asbestos fibers has been linked to serious health problems such as lung disease, mesothelioma and other types of cancer. The Environmental Protection Agency (EPA) says that exposure to asbestos is only dangerous when asbestos is airborne. The fibers are invisible to the naked eye and are easily inhaled.

A spokeswoman for Toys 'R' Us, which distributes the one of the crime kit toys, responded to the report, saying that safety is the company's highest priority, CBS reported.

"We require that every product we carry meets or exceeds all applicable state and federal laws, industry standards, codes and requirements. At this time, we are reviewing the referenced report, along with supplier test reports, to ensure full compliance to our strict safety standards," Kathleen Waugh, vice president of corporate communications at Toys R' Us, said in a statement.

Asbestos was once a common insulation material used in buildings, but is now rarely used in the United States and is banned in many developed nations due to its carcinogenic properties, EWG said.

The EWG Action Fund report does not state the amount of asbestos that was found in each of the products.